1. Field of the Invention
The present invention relates to a method of scrubbing flue gases coming from a firing unit, including the steps of adding dry, fine-grained absorbent that contains at least one alkaline earth, and subsequently separating dust from the flue gases. The present invention also relates to an apparatus for scrubbing flue gases coming from a firing unit, and includes a combustion chamber, means for adding absorbent to the combustion chamber and/or the flue gases, and a subsequently connected dust connector.
3. Description of the Prior Art
German Offenlegungsschrift 30 15 977 Holter et al dated Nov. 5, 1981 discloses a method of the aforementioned general type, according to which, preferably subsequent to a first dust separation stage, the absorbent is blown into a dry reaction section, and the thus treated flue gas is subjected to the separation of dust in a further subsequently connected dust collector or separator. All of the flue gas leaving the firing mechanism (boiler firing or fluidized bed firing) is conveyed through the dry chemical absorption reaction section. The absorbent serves to extract SO.sub.2, HF, HCl from the flue gas, with named examples for the absorbent including: calcium hydroxide, calcium carbonate, and fine white lime.
German Offenlegungsschrift 29 05 719 Mohn et al dated Aug. 21, 1980 discloses a method of scrubbing flue gas via an absorption liquid, with subsequent spray drying. Prior to being treated with a liquid, the flue gases are divided into two partial streams, one of which is supplied to a spray drying phase of a concentrated salt solution that forms during the treatment, and is then supplied to a subsequent dust separation phase, while the other partial stream is again combined with the first partial stream prior to the flue gas scrubbing phase. This combination of the partial streams can also take place prior to the dust separation phase.
An object of the present invention is to provide a method and apparatus of the aforementioned general types with which, in a simple manner, the extraction of harmful or noxious gases from the flue gas can be improved.